We report the association of the recently discovered hard X-ray source IGR J17475 - 2822 with the giant molecular cloud Sgr B2 in the Galactic Center region .
The broad band ( 3–200 keV ) spectrum of the source constructed from data of different observatories strongly supports the idea that the X-ray emission of Sgr B2 is Compton scattered and reprocessed radiation emitted in the past by the Sgr A ^ { \star } source .
We conclude that 300–400 years ago Sgr A ^ { \star } was a low luminosity ( L \approx 1.5 \times 10 ^ { 39 } erg s ^ { -1 } at 2–200 keV ) AGN with a characteristic hard X-ray spectrum ( photon index \Gamma \approx 1.8 ) .
We estimate the mass and iron abundance of the Sgr B2 scattering gas at 2 \times 10 ^ { 6 } M _ { \odot } ( r / 10 { pc } ) ^ { 2 } and 1.9 solar , respectively ( where r is the radius of the cloud ) .